There is a great deal of interest in polymers such as polyimides or poly(amide-imides) which are thermoplastic in nature and can be fabricated by conventional molding techniques or are soluble and can be used as coatings, adhesives and the like.
It is disclosed, for example, in U.S. Pat. Nos. 3,699,075 and 3,812,159 to Lubowitz, U.S. Pat. No. 3,847,867 to Heath et al and U.S. Pat. No. 3,879,428 to Heath that aromatic diether polycarboxylic acids and anhydrides thereof could be reacted with aromatic diamines to prepare thermally stable, high molecular weight polyimides which are soluble in organic solvents and fusible. Such polyimides are suggested as being suitable for use in preparing coatings, adhesives, films and the like or for fabrication into useful parts by conventional molding equipment. However, known polyimides prepared in this manner appear to exhibit generally poor solvent resistance.
Recently, as disclosed in U.S. Pat. No. 4,395,527, it has been found that the properties of a variety of polymers can be improved by the presence of a siloxane unit of formula ##STR1## wherein Q is a substituted or unsubstituted aromatic group;
Z is ##STR2## D is substituted or unsubstituted hydrocarbylene; R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 each independently is substituted or unsubstituted hydrocarbyl; PA1 x, y and z each independently has a value from 0 to 100; PA1 and that polymers such as polyimides and poly(amide-imides) containing these units are generally thermoplastic and soluble in conventional solvents. PA1 Z is ##STR5## D is unsubstituted or substituted hydrocarbylene; R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 each independently are substituted or unsubstituted hydrocarbyl; PA1 x, y and z each independently has a value from 0 to 100. PA1 E.sup.3 is ##STR12## or linear or branched alkylene of 1 to 8 carbon atoms. PA1 Q is substituted or unsubstituted carbocyclic aromatic of 6 to 18 ring carbon atoms or substituted or unsubstituted heterocyclic aromatic of 5 to 18 ring atoms where the hetero atoms are selected from N, O and S, and where the substituents are alkyl of 1 to 12 carbon atoms, alkenyl of 2 to 12 carbon atoms, alkynyl of 2 to 12 carbon atoms, cycloalkyl of 4 to 8 carbon atoms, alkoxy of 1 to 12 carbon atoms, alkylthio of 1 to 12 carbon atoms, phenyl, alkylphenylene having 1 to 12 carbon atoms in the alkyl group, phenoxy, phenylthio, alkylcarbonyloxy of 2 to 12 carbon atoms, phenylalkylene of 1 to 12 carbon atoms in the alkylene group, alkylcarbonyl of 2 to 12 carbon atoms, alkoxycarbonyl of 2 to 12 carbon atoms, bromo, chloro, fluoro, iodo, nitro, cyano, cyanothio, carboxy, carbonyl, hydroxy, mercapto, formyl, thioformyl and mercaptocarbonyl; PA1 D is substituted or unsubstituted hydrocarbylene of 1 or 3 to 18 carbon atoms; PA1 R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 each independently, is an unsubstituted or substituted alkyl of 1 to 12 carbon atoms, alkenyl of 2 to 12 carbon atoms, alkynyl of 2 to 12 carbon atoms, cycloalkyl of 4 to 8 carbon atoms, phenyl, alkylphenylene where the alkyl group contains 1 to 12 carbon atoms, phenyalkylene where the alkylene group contains 1 to 12 carbon atoms, or alkenylphenylene with 2 to 12 carbon atoms in the alkenyl group and when substituted, these hydrocarbyl groups are substituted by Br, Cl, I, F, --NC, --NO.sub.2, --OCN, alkoxy of 1 to 8 carbon atoms, --S--(C.sub.1 -C.sub.8)alkyl, ##STR13## --S--S--(C.sub.1 -C.sub.8)alkyl, --COOH, --COSH, --CSOH, --CONH.sub.2, --CN, --CHO, --CHS, --OH, --SH, --NCO and --NR.sub.a R.sub.b where R.sub.a and R.sub.b indpendently are hydrogen or lower alkyl. PA1 R.sub.c is each independently lower alkyl, lower alkenyl, lower alkynyl, cycloalkyl of 4 to 8 carbon atoms, lower alkoxy, lower alkylthio, phenyl, lower-alkylphenylene, phenyl-loweralkylene, lower-alkenylphenylene, phenoxy, phenylthio, lower-alkylcarbonyl, lower-alkylcarbonyloxy, lower-alkoxycarbonyl, bromo, chloro, fluoro, iodo, nitro, cyano, cyanothio, carboxyl, carbonyl, hydroxyl, mercapto or mercaptocarbonyl; PA1 Z is ##STR15## D.sub.1 is methylene or alkylene of 3 to 8 carbon atoms; R.sup.10 is lower alkyl, lower alkenyl, lower alkynyl, phenyl, lower alkylphenylene, phenyl-loweralkylene, or loweralkenylphenylene. PA1 B is a divalent residue as hereinabove defined; and PA1 r is an integer greater than 1, and preferably from 10 to 10,000.
In addition to being soluble and/or thermoplastic, it would be highly desirable of the properties of such kinds of polyimides or poly(amide-imides) containing or not siloxane units could be modified to meet specific needs without substantial loss of the desirable mechanical, electrical, thermal and other qualities of the polymer.